Fluid pressure device



July 6, 1948. H. E. soMEs ETAL 2444474f FLUID PRESSURE DEVICE l FiledJune 6, 1944 2 Sheets-Shee1'I 2 INVENT Howard E' Some Benjam z'n R Parz/z'n Patened July 6, 1948 cuirso s mrss TEN T ffOF'FICE 'to Thie* Ohio=Crankshaft Company, Cleveland,

Ohio, afcorporation of Ohio Application June '6, 1944, Serial No. 538976`This vinvention relates 'to re'ciprcca'ble work 'suppor'ting carriagesand the like, 'particularly `vto 'devi'e's of this nature adapted to bereciprocated i'n `generallyvertica1 V'dir'ection through the me- 'diuinof a fiu'id under pressure.

In various types of rn'ech'an'isms, such as for example, machine tools,heat treating equipment and the like, a carriage or head is frequentlycaused to recip'rocate i'n a 'generally Vertical 'di- 'rect'ion throughthe provision of 'fluid pressure cylinders and pistons. Particularly, inconstruc- 'tions of this Character wherein the carriage or head and thework or tool carried thereby is severalliundred pounds 'in weight,serious damage 'to 'the'equipment is likely to result in the event theifluid pressure 'should 'fail when the lcarriage or head is 'in an"elevate'd position.

'The object of 'the present invention is to -provide a generallyVertical fiuid *piston andcylinder iarran'ge'inent 'of novel'construction wherein 'improved means is provided for preventingrelative inoveinent between the parts inthe event of fluid pressurefailure.

Another 'object 'is the provision in 'a cylinder and piston arrangeinentadapted to be relatively reciprocatecl 'by fiuid 'under pressure of 'anovel and 'ir'nproved lcheck valve arange'rnent 'which duic'kly and'automatically functions to 'prevent relative reciprocation of the partsin the `'event *of lfiiiid pressure failure.

With the above 'and jo'ther objects in view which will be 'apparent fromthe 'following description'to those 'skilled in theart `to which theinvention appertains, 'the present invention vvconsists in certainfeatures of construction and 'co'rribinations of parts to b'ehereinafterdescribed 'with reference to the accor'npanying drawings, and thenclaimed.

In the drawings which illustrate bodimen-t of the inventio'n:

Figure l is a front elevation of a heat treating machine having Vavertically reciprocable carriage in which the features'of the presentinventio'n 'are in'ccrporated;

Figu're 2 is an *enlar'ged lon'g'itudinal section of a p'o'rtion of oneof the carriage actuating cylinders 'and 'pistons Fgures 3, 4, andaretransverse'sectionstaken `'s'ubtariti'ally 4on the lines 3 -3, 4-44,and `5--5, respectively, of 'Figure 2,'

Figures G'an'd 7 are'diagrammatic 'views show- *i'ng ztwo sta'ges ofoperation of the cylinder and a suitable em- "pi'sytc'n arrangernent and"Figf is a section through antinterlocking relief *Valve 5 iClaims. (Cl.121-'--40) 2 Referring to the -drawings, the machine 'selected foril'lustration is a 'heat "'trea'ting machine 'adapted to heat treat thebore of an elongated cylindrical member lt which is moved ve'rticallyand longitudinally by the reciprocah'le Ycarriage, generallydesigna'te'd i I, Irelative t-oheatin'g and quen'ching 'heads tE and IS,i'espectively.

The 'carriage 'I'l einbo'dies 'spaced Vertical oylyinders l'finterconn'e'cted 'by spaced 'cross heads i and 'HS which carry chu'ckingVmembers "I'! ``for holding ithe tubular member *NJ lin axi'alalignm'ent -with the heating and 'quenching heads FZ and 13. Theca'rriage cylinders till 'are 3recip'rocabiy supported ion spacedVertical rods W `ysecuredi'by suitable clamps 19 'toithe 'iiia'chinebase 2'9.

The rcds 133 farfe prefer'ably comprisedfo'ffafsolid intermediatesection '2| fan'd tubula'r upper "and lower. Sections "22 having'tapered ``te'lescopirig '-"fi'ts 'as -in'dicated at 23 in Figure 2,'the intermediate section being provided 'With `'coupling co-llars124labutting Shoulders '25 "afnd th're'adefd'to the tubu- -lar upper andlower Sections `2 I.

The 'intermediate section 22| -is provided With an enlarged por'tion 26substantially n'ridwiay between theends 'of the r'od 1i8 with which thecylinder Hi lhas Vsealedsliding engagement. H1- though'not shown inFigures .1. andfiz Aof 'thedrawings, 'the opposite ends -of thecylinders ih'ave sealed sliding engagement with the rod/sections v22.

The intermediate section 2| is provided with two longitudinal passages*Z' and 28, the passage '2"i opening -into the cylinder space -abo've`the piston portion 328 through portl!! which is ``closed by the checkvalve 30, shown in ``Figure 3, -and the passage 28 opening into thecylinder space below 'the =p`iston portion 2B through ports 73'I.

passage 34 which opens 'through'the seat 33. =Arranged 'above the seat33 and 'intersecting the passage 32 is a cross passage35 whichplacesthepassage 32 in 'communication fwith -thecylinder space above the`pistonportion '28. Disposed in the passage 3'2 is a longitudinall'yimovable slide spaced intermediate piston portions 38 and 39 and anupper shank portion 40 surrounded by a compression spring 4|. Threadedin the upper end of the passage 32 is a plug 42 having a recess 43Within which the shank portion 40 is adapted to slide. The compressionspring 4| abuts the plug 42`and the piston portlon 39 and urges thevalve 36 downwardly whereby the lower portion 31 engages seat 33 to haltmovement by the spring. In this position of the valve, the spaced pistonportlons 38 and 39 are disposed as seen in Figure 2 at opposite sides ofthe cross passages 35. The high pressure passage 21 is also providedwith a passage 44 which opens into the passage 32 between the pistonportions 31 and 39.

Figure 6 diagrammatically illustrates the fluid fiow to one of thecylinders |4 (the upper) during elevation of the carriage Fluid underpressure flowing through the high pressure passage 21 opens the checkvalve 30 and flows through passage 29 into the upper end of thecylinder. A passage 45 is provided for draining leakage fiuid from thepassage 32 above the valve 36.

The fluid control system -is so arranged that under normal operation apredetermined pressure is maintained in the low pressure passage 28during the up stroke of the cylinder |4 and in the event of a drop inpressure in the line 21, the pressure in passage 28 will drop below thepredetermined value. This pressure in passage 28 in normal operation issuch that upon initial upward movement it will raise the slide valve 36from its seat to the position shown in Figure 6, thus plaoing the crosspassages 35 in communication with each other.

During the downward movement of thevcarriage, as depicted in Figure '1,low pressure fluid flows through passage 28 and thence through passage3| into the lower end of the cylinder to cause the downward movement.This fiuid is under suflicient pressure to flow through passage 34 andkeep the slide valve 36 raised from its stop seat against the resistanceof the spring 4| which keeps the passages 35 and 44 in communicationwith each other whereby the fluid in the upper end of the cylinder flowsthrough these passages and thence through passage 21 back to the sourceof fluid supply. During this movement, the check valve 30 maintains thepassage 29 closed.

Should the fluid pressure in passage 28 fall, incldent to fluid -linebreakage to either conduit 21a, or 28a, pressure pump failure or anyother cause, during either upward or downward movement of the carriageand drop below the predetermined value necessary to overcome theresistance of the compression spring 4|, the compression spring 4|immediately moves the slide valve 36 downwardly to its seat 33, thisbeing the position shown in Figure 2. The valve portion 39 thus closespassage 32 between the passages 35 and 44. Also, under the condition ofa drop'in pressure in the high pressure line 21 the check valve 30closes communication between the passages 21 and 29, just as it does forall return flow from the cylinder to the passage 21.

The fluid 'in the upper end of the cylinder |4 which normally flows backto the source through passage 21 is thus trapped in this end of thecylinder and accordingly prevents the cylinders and the carriagesupported thereby from dropping and causing damage to the mechanism orthe work or tools supported by the carriage.

VTo summarize, in normal operation as long as and 44 working pressure ismaintained in the passage '21 the pressure in passage 28 is permitted toremain at least high enough to hold the valve 36 in its upper .positionagainst the spring 4|' and the passages 35 and 44 are continuously keptin communication with each other. Under these normal conditions theparts are lowered by an active pressure in conduit 28 which, with theassistance of gravity, is sufiiclently high to force the parts downagainst the reduced pressure in the conduit 21. Due to resistance inconduit 21 to the outfiow of fluid, after the ,high pressure supply hasbeen cut off and the passage has been opened to exhaust, and to theaction of fiuid in passage 28 on the cylinder, the pressure in conduit21 is still high enough to elevate the parts and would do so except forthe greater pressure in conduit 28 tending to force the parts down. Butif the pressure in conduit 21 fails this causes pressure in conduit 28to fall below that necessary to hold valve 36 open and when this valvecloses it traps fiuid in the upper end of the cylinder (check valve 3|]closing against any outfiow through passage 29) so that it is impossiblefor the parts to fall until the normal minimum pressure is againestablished in conduit 21. The low pressure or lack of pressureestablished in conduit 28, permltting valve 3B to close, prevents anyappreciable tendency to force the parts down against the fluid trappedin the upper cylinder Chamber.

A simple device for providing this control is shown'in Fig. 8 where apiston 46 in a cylinder 41 is moved by high pressure in conduit 21aagainst a spring 48 to keep closed a relief line 49 from the lowpressure conduit 28a. When pressure in conduit 21a fails, it opens therelief line 49, thus lowering the pressure in conduit 28a and permittingvalve 36 to close to trap fluid in the upper end of the cylinder toprevent it from falling. f

While the invention is shown and described in connection with onecylinder and piston arrangement only, it is to be understood that it maybe under for both cylinder and piston arrangements if necessary. It isto be understood also that the inventlon is applicable to any characterof machine having a single or multiple cylinder carriage.

Various changes may be made in the detailed construction andarrangement'of the parts described without departing from the spirit andsubstance of the invention, the scope of which is defined by theappended claims.

What ls claimed is:

1. A fiuid operated device including a cylinder element and a pistonelement Operating in the cylinder to define two pressure chamberstherewith and having a piston rod extending in sealed relationtherefrom, one of said elements of the fluid Operating device beingfixed and the other being movable, a first passageway in said piston rodopening into a first one of said cylinder chambers on one side of thepiston, a second passageway in said piston rod opening into a second oneof said cylinder chambers on the other side of the piston, a valvechamber in said piston rod, axially spaced passages opening from saidvalve chamber, one into said first passageway and the other into saidfirst cylinder chamber, a third valve passage connecting one end of thevalve chamber with said second passageway, a valve in said valvechamber, spring means urging said valve into position to close theconnection between said first and second valve passages,

and said third valve passage entering the valve Chamber at one end ofthe valve to permit fiuid from the second passageway to move it againstits spring to keep the first and second valve passages connected as longas sufficient pressure exits in said second passagewair and to close theconnection when the pressure drops below that necessary to oppose thespring.

2. A fluid operated device including a cylinder element and a pistonelement Operating in the cylinder to d-efine two pressure chamberstherewith, said fluid operated device having first and second fiuidpassageways for conducting fluid to and from said chambers to effectelevating and lowering movement of one of said elements and means formaintaining a predetermined pressure on fluid being conducted from onechamber of the cylinder by the second of said passageways as a result offluid being conducted to the other chamber of the cylinder by the firstsaid passageway, two outlets from the first passageway to its cylinderChamber, a check valve for a first one of said outlets for preventingreturn flow from the chamber to said first passageway, valve means forthe second one of said outlets, spring means urging said valve means toa position to close said second Outlet, said valve means beingresponsive to fiuid pressure in said second passageway during elevatingand lowering movements to open said second outlet and being responsiveto drop in pressure below a predetermined limit necessary to oppose saidspring to close said second outlet and trap fiuid in the chamber of thecylinder to prevent said lowering movement.

3. A fluid operated device including a cylinder element and a pistonelement Operating in the -cylinder to define two pressure chamberstherewith and having a piston rod extending in sealed relationtherefrom, one of said elements of the fiuid operated device b-eingfixed and the other being movable, a first passageway in said piston rodopening into a first one of said cylinder chambers on one side of thepiston and a second passageway in said piston rod opening into thesecond one of said cylinder chambers on the other side of the piston,valve means for controlling the flow of fiuid from said first Chamber tosaid first passageway, and means responsive directly to pressure offluid in said second passageway for keeping said valve means open, saidlast-mentioned means being responsive to a failure of pressure in saidsecond passageway for closing said valve to trap fluid in said firstchamber, the control system for the said first and second passagewaysincluding means for causing pressure in the second passageway to fallbelow the predetermined value necessary to keep said valve means openupon sufiicient failure of pressure in said first passageway.

4. A fluid operated device including a cylinder element and a pistonelement Operating in the cylinder to define two pressure chamberstherewith, said fluid operated device having first and second fluidpassageways for conducting fluid to and from said chambers to effectelevating and lowering movement of one of said elements, two outletsfrom the first passageway to its cylinder Chamber, a check Valve for afirst one of said outlets for preventing return fiow from the chamber tosaid first passageway, valve means for the second one of said outlets,and means responsive directly to pressure of fluid in said second andthrough the pressure of fluid in said second passageway which is madedependent upon pressure of fiuid in said first passageway for lreepingsaid valve means open during operation except upon pressure failure ineither the or second passageway.

5. A fluid operated device including a cylinder element and a pistonelement Operating in the cylinder to define two pressure chamberstherewith and having a piston rod extending in sealed relationtherefrom, one of said elements of the fiuid operated device being fixedand the other being movable, a first passageway opening into a first oneof said cylinder chambers on one side of the piston and a secondpassageway opening into the second one'of said cylinder chambers on theother side of the piston, and control means, including a valve forycontrolling the flow of fluid from said first Chamber to said firstpassageway, for closing said first passageway upon failure of pressurein either of said passageways, said control means including interactingmeans for causing pressure in said second passageway to drop and saidvalve to close upon failure of pressure in said first passageway.

HOWARD E. SOMES. BENJAMIN R. PURVIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNXTED STATES PATENTS Number Name Date 993,967 Debauche May 30, 19111,960,3'79 Havens May 29, 1934 2,027,706 Schauer Jan. 14, 1936 2,186,266Onions Jan. 9, 1940 2,216,486 Cooke Oct. 1, 1940 2,328,979 Herman Sept.7, 1943 2,363,196 Nye Nov. 21, 1944 FOREIGN PA'I'ENI'S Number CountryDate 432,390 Great Britain July 25,` 1933

